Electrical connector



Oei. 13, 197@ F. c. RUSHING 3,534,320

ELECTRICAL CONNECTOR Filed Aug. lo, 196e I Q le ATTORNEY United StatesPatent O 3,534,320 ELECTRICAL CONNECTOR Frank C. Rushing, Ellicott City,Md., assiguor to Westinghouse Electric Corporation, Pittsburgh, Pa., acorporation of Pennsylvania Filed Aug. 10, 1966, Ser. No. 571,615 Int.Cl. H01r 13/54 U.S. Cl. 339-45 10 Claims ABSTRACT F THE DISCLOSURE Anelectrical connector for use in vacuum, explosive environmentsincorporating mating abut type contacts in a lever driven cam operatedconnector assembly. The movable contact assembly is moved through anarcuate path during connector engagement and disengagement therebyestablishing a shear force between the contact surfaces of theconnector. This motion produces contact wiping action which providesgood electrical contact and exerts sufficient force to disengage thecontacts under high friction or weld conditions experienced under vacuumconditions. A spring loaded shield is provided to isolate the connectorcontacts from the external atmosphere during contact engagement anddisengagement to eliminate the hazards of explosion.

This invention relates to electrical connectors, and more particularly,to electrical connectors adapted for use under high vacuum conditionssuch as found in space.

There are many diflcult problems encountered in the design of electricalconnectors to be used in the high vacuum conditions of outer space. Agood electrical connection requires intimate contact between twoterminals, preferably made of soft metals which are wiped together underpressure. Unfortunately, as the degree of vacuum is increased, thefriction coefficient between the contacts and the chance of welding thecontacts increase. Although considerable progress has been made in thedevelopment of materials that will maintain low friction coecients andwill withstand welding, the operation of terminals made of thesematerials under a variety of conditions in a high vacuum is stillquestionable.

More specifically, the use of a typical female-male connector of theprior art has been unsatisfactory under high vacuum conditions.Typically, such connectors present large surfaces which are brought intointimate contact with each other under pressure to thereby provide abetter electrical connection and also to remove insulating contaminants.However, the use of such contacts in a high vacuum environment isaccompanied by higher wiping forces due to the higher coefficient offriction between the surfaces of the male-female contacts and theterminals may even weld together. In order to separate contacts of thistype, it would be necessary to exert a large force upon the respectiveterminals thereby possibly galling the contacts or damaging theirsupports.

The connector of this invention has been designed so that the terminalsmay be connected and disconnected with a manual action of minimumcomplexity and minimum effort. Typically, the person using thisconnector will be an astronaut dressed in a space suit. The manualdexterity of an astronaut is limited by the pressurized space suit andby the unfamiliar gravitational field. As a result, the connector ofthis invention must be designed to avoid tediousness in mating the twoparts of the connector and to avoid diiiculty of forcing the two partstogether or apart.

It is, therefore, an object of this invention to provide a. new andimproved electrical connector adapted to be used in a high vacuumcondition with a simple manual act and minimum effort.

3,534,320 Patented Oct. 13, 1970 ICC It is a further object of thisinvention to provide a new and improved electrical connector whereby theproblems encountered in a high vacuum condition of increased frictioncoeicients and of welding the surfaces of the terminals are overcome.

It is a more particular object of this invention to provide a new andimproved electrical connector having a high density of terminals andcapable of providing a high shearing force to disengage any highfriction or welded terminals.

It is a still further object of this invention to provide a new andimproved electrical connector which is sealed against dust and humidity,and which will prevent any possible arcing between the terminals fromigniting the surrounding atmosphere.

These and other objects are accomplished in accordance with theteachings of the present invention by providing a new and improvedelectrical connector including rst and second assemblies for supportingin high density arrays iirst and second sets of contacts to be matedwith each other. The contacts of one of said sets are spring biased in adirection substantially perpendicular to the mating surface of thecontacts of the other set. A lever is pivotally mounted upon one of theassemblies for engaging and disengaging the sets of contacts to and fromeach other. More speciiically, the lever has a first cam surface forexerting an engaging pressure on the other assembly, and a second camsurface for exerting a disengaging force upon the other assembly and forestablishing a shearing force upon the sets of contacts. The lever ispivotally mounted upon one of the assemblies so that the point ofpivoting is approximately in the plane in which the contacts of bothassemblies engage each other. As a result, a high mechanical advantagewill be achieved and a high shearing force will be exerted upon thecontacts to thereby disengage any welded contacts with relatively littleforce exerted upon the lever.

These and other objects and advantages of the present invention willbecome more apparent when considered in view of the following detaileddescription and drawings, in which:

FIGS. 1 and 2 show side views of an electrical connector in accordancewith the teachings of this invention in which there is particularlyillustrated the details of the lever and detent mechanisms of anembodiment of this invention;

FIG. 3 is a sectional view of the electrical connector shown in FIGS. land 2;

FIG. 4 is an enlarged, detailed view of the mating electrical contactsas incorporated in the electrical connector of FIGS. l, 2 and 3; and

FIGS. 5a and 5b show diagrammatically how a shearing force is developedupon the contacts of the electrical connector of this invention.

Referring now to the drawings and in particular to FIGS. 1 and 2, thereis shown an electrical connector 10 including an upper assembly 12 and alower assembly 14 for supporting in high density arrays two sets ofengaging contacts. Cables 16 and 20 are respectively inserted throughappropriate sealing members 18 and 22 such as grommets made of asilicone rubber into the assemblies 12 and 14. The sets of the contactsassociated with the assemblies 12 and 14 are engaged and disengaged by aset of levers 24 which are pivotally mounted upon pins 32 associatedwith the lower assembly 14. More specifically, the pins 32 are securedin a suitable manner to support members 36 which in turn are securedupon the periphery of the assembly 14. Further, the levers 24 includehandles 26 which extend away from the pins 32, and cam surfaces 28 whichengage a set of second pins 34 for exerting an engaging force upon theassembly 12 moving it downward and slightly to the right. The pins 34are secured to support members 38 which are in turn disposed upon theouter surface of the upper assembly 12. Further, the levers 24 have camsurfaces 30 which when the levers 24 are rotated in a counterclockwisemotion (as seen in FIG. 1) exert a force upon the pin 34 and the upperassembly 12 moving it upward and slightly to the left. The slightmovements to the right and to the left provide a wiping action betweenthe electrical contacts which is desirable both for closing (to make agood connection) and for opening (to shear welded contacts a art).

pA detent 42 is provided to latch the levers 24 and to insure that theassemblies 12 and 14 are held together when the electrical connector isengaged. More specifically, the detent 42 is pivotably supported uponthe lower assembly 14 by a pair of projections 40 and a pin 44 disposedtherebetween. The detent 42 is pivotally mounted upon the pin 44 and hasa recess 50 for engaging a latching bar `48. Further, the spring 46 isdisposed between the assembly 14 and the detent 42 tot bias the detent42 in a clockwise direction (as seen in FIG. l) and to secure thelatching bar 48 within the recess S0. The latching bar 48 may bereleased by depressing the detent 42y (and therefore the spring 46) andthe latching bar 48 to remove the bar 48 from the recess 50.

Referring now to FIG. 3, the upper assembly 12 includes side walls 52having recess portions 53 for receiving a terminal board 58 upon whichthere is disposed one set of the contacts. A top wall S6 is secured tothe side walls 52 as by suitable fasteners S4 which extend through theside wall 52 and the terminal board 58 to secure the terminal board 58in place. Further, the terminal board S8 has a plurality of closelyspaced openings 60 for receiving a set of contact assemblies 104. Thecable 16 extends through an opening within the upper wall 56 andincludes a plurality of wires 17 which are each connected to one of thecontact assemblies 104 by a suitable process such as soldering. In orderto protect the wires 17 from moisture, vibration, and shock, a sealingplug `62 having a plurality of openings 64 is inserted within theassembly 12 so that the wires 17 are disposed through the openings 64 tobe connected with the contact assemblies 104.

The lower assembly 14 includes side walls 66 and a bottom wall '78secured to the side wall 66 by appropriate fasteners 81. Further, theside walls 66 have recesses 67 for receiving a terminal board 68 forsupporting a plurailty of sliding terminal assemblies 90. Morespecifically, the terminal board 68 includes a base member 69 havingprojections 71 which are disposed within the recess portions 67 and aresecured therein by the fasteners 81. The base member 69 includes aplurality of openings 74 into which the terminal assemblies 90 aredisposed and a pair of retaining members 70 and 72 disposed on eitherside thereof for confining the assemblies 90. As shown in FIG. 3, theretaining members 70 and 72. are secured to` the base member 69 by aplurality of simple fasteners such as screws 79. The cable includes aplurality of wires 21 which are disposed through the wall 66 and areconnected to each of the terminal assemblies 90. More specifically, eachof the wires 21 is fed through an opening 77 within a sealing plug 76which serves to protect the wires 21 against moisture, shock, andvibration.

During the engagement and disengagement of electrical contacts,electrical discharges may occur between the spaced contacts. If thesedischarges were to occur in a combustible atmosphere, there would be agreat probability of igniting this atmosphere. In order to prevent suchexplosions, there is provided a sealing ring 80 which is spring biasedby springs 82 in a vertical drection (as shown in FIG. 3). The sealingring 80 extends above the assembly 14 to engage the upper assembly 12before the mating contacts engage. As the assemblies 12 and 14 arebrought together, the sealing ring 80 is forced downward against thesprings 82 thus shielding. the terminal assemblies 90 and 104 `from thesurrounding atmosphere. More specifically, the sealing ring ts into arecess 83 formed by the terminal board 68 and side walls 66 and is heldtherein Iby a plurality of stops 86 which project from the side walls 66into corresponding guide slots 84. The position of the stops '86 and thelength of the guide slots 84 determine the extent 0f movement of thesealing ring 80.

Referring now to FIG. 4, there is shown a detailed view of the slidingterminal assembly 90 mounted upon the lower assembly 14 and thestationary terminal assembly 104 disposed upon the upper assembly 12.The stationary terminal assembly 104 includes a terminal 103 which isinserted within the opening 60 of the terminal board 58. The terminal103 has an enlarged portion 107 which is disposed within a recess 61 andwhich has a contacting surface 106 disposed to abut the terminalassembly 90. The terminal 103 is secured to the terminal board 58 by awasher 108 which is fastened to one end of the terminal 103i as bysoldering.

The sliding terminal assembly 90 includes a terminal member 92 having anextending portion 91 which is disposed through an opening 73 disposedwithin the retaining member 72. The terminal member 92 has an enlargedportion 94 which abuts against one side of the retaining member 72 and awasher 96 which is secured as by soldering to the extending portion 91to thereby secure the terminal member 92 upon the retaining member 72.Further, the terminal member 92 has a projecting portion 93 upon whichthere is secured a spring 98 as by welding to firmly mount the spring 98upon the terminal member 92 and to insure a good electrical connectiontherebetween. The terminal assembly 90 includes a plunger contact 100which is upwardly biased (as shown in FIG. 4) by the spring 98. Theplunger contact 100 includes an enlarged portion 101 which abuts againstthe retaining member 70 and a contact portion 102 which extends throughan opening 76 within the retaining member 70 to make contact with thecontact surface 106 of the terminal 103. Further, the plunger contact100 has a projecting portion 109 to which the spring 98 is `firmlysecured as by welding. The diameter of the opening 76 and the thicknessofthe retaining member 70 are accurately controlled to insure that themovement of the contact portion 102 is confined to a directionsubstantially perpendicular to the contact surface 106 of the terminal103. -If the opening 76 becomes too large, it may wobble as it is beingdepressed and may be cocked against the sides thereof. The spring 98 maybe made of beryllium copper and be allowed to deflect about 1/16 inchduring engagement so that the contact portion 102 would exert about 1%pound of compressive for-ce against the surface 106, Illustratively, theterminal assemblies 90 could b e spaced from each other by a distance ofapproximately 9/16 of an inch and disposed in a regular array withapproximately 25 contacts disposed within one square inch.

In one particular embodiment of this invention, one of the terminalcontacts was made of niobium disellenide and the other contact was madeof silver. These contact materials have demonstrated that they canwithstand in vacuum, a high shearing action with no noticeable damage tothe contact surfaces. Referring to FIG. 4, it is noted that contactsurface 106 is planar whereas the contact portion 102 presents aspherical surface. It is an important aspect of this invention that thecontact configuration provides sucient contact area with a controlledminimum of sliding during engagement. Alternatively, the abuttingsurface 106 as well as abutting surface 102, may be spherical. Further,the sealing members 18 and 22 may be made of silicone rubber whereas theterminal boards and the other dielectric members may be made of asuitable insulating material such as polyamide or Teon (a trademark fora tetrafluoroethylene polymer of the Du Pont 6). The enclosure includingthe side Walls and the top walls may be made of a silver plated aluminumand the springs, pins and bar members may be made out of an austeniticstainless steel. The other members of the terminal assembly made may beof beryllium copper. In addition, the various joints of the device maybe lubricated with a molybdenum disulphide.

It is an object of this invention that when the levers 24 are rotated ina counterclockwise direction (as seen in FIG. l) that an upward orvertical force and a shearing or horizontal force is exerted through thepin 34 upon the upper assembly 12. Referring now to FIG. A, theoperation of the mechanism of this invention will now be explained. Thespring 98 forces the plunger Contact 100 upward so that the terminal 103and the plunger contact 100 abut each other respectively at theircontact surfaces 106 and 102. Significantly, the terminals or contactsof this invention are of the non-reentrant or abutting variety whichmake contact with each other along a point or limited surface which ispreferably as planar as possible. The use of abutting contacts isdesired where a shearing force is applied to the contact surfaces. If alateral or transverse shearing force was applied to contacts which werefitted together, the shearing force would be unable to move the contactswith respect to each other thus possibly damaging the contacts. Asmentioned above, the plunger contact 100 is substantially confined to amotion along a path which is substantially perpendicular to the contactsurfaces 102 and 106. Further, as the lever 24 is moved in acounterclockwise direction, the upper assembly as Well as each of thestationary terminal assemblies 104 and terminals 103 will be movedupwardly along an arcuate path designated by the number 110'. Referringto FIG. 5A, there is shown a point P about which the arcuate path 110 isrotated. Further, the point P is located in a plane designated by thenumeral 112 and which may be defined as that plane which issubstantially perpendicular to the direction in which the plungercontact 100 is confined and passing through a point on this linecoinciding with the contact surfaces 102 and 106 when the respectiveterminals 100 and 103 are in a fully engaged condition (i.e. with thesprings 98 depressed).

Thus, in operation when the upper assembly 12 is moved along the arcuatepath 110 by the levers 24, a first motion component identified by theletter B is directed in a vertical direction from the terminal 103 and asecond motion component identified by the letter A is directed along ahorizontal path within the plane 112. The motion of the component of theupper assembly 12 identified by the letter A exerts a force which actsto break the possible welds between the terminal 103 and the plungercontact 100. In a preferred embodiment of this invention, the terminals103 are moved through an arcuate path having a center point P which isin the plane 112. As a result of such an arrangement, the relativelylarge upward motion of the terminal 103 imparts a relatively smallhorizontal motion of the terminal 103. Thus, a mechanical advantage isrealized and a nominal upward force exerted upon the terminal 103 willresult in a large horizontal shearing force exerted upon the terminals100 and 103.' As shown in FIG. 5A, the vertical and horizontalcomponents of the force exerted on the contacts may vary. At the instantof starting when the contact surfaces 102 and 106 lie in the plane 112,The ratio of the upward component to the horizontal component istheoretically infinite and there results in practice a high mechanicaladvantage for shearing the contact surfaces. Further, since the plungercontacts 100` are rmly supported within the openings 76, the shearingforce as developed by the lever is positively exerted upon the contactsurfaces 106 and 102. In one particular embodiment of this invention,the pins 32 and 34 were spaced 3/s of an inch apart; as a result,vertical motion of Ms inch apart at the upper assembly 112 resulted in ahorizontal portion of only .038 inch thereby achieving a mechanicaladvantage of over 3 to 1 at the end of the movement of the levers 24. Itis noted that an additional mechanical advantage is achieved due to themanner in which the levers 24 act upon the upper assembly 12. Morespecifically, a force exerted upon the end of the handle 26 acts througha moment arm whose length is substantially equal to the length of thehandle 26, whereas the moment arm which acts upon the pin 34 is only ofa length equal to the distance between the pin 32 to the cam portion 30.

In order to maximize the mechanical advantage of the force exerted uponthe levers 24, the point P about which the arcuate path 110 rotates isplaced in the plane 112. If the point P is displaced from the plane 112,the mechanical advantage and thus the forces exerted upon the terminal103 of the electrical contact 100 would be decreased. More specifically,if the point P is displaced from the plane 112, a vertical motion alongthe arrow B Would result in a relatively greater horizontal motion inthe direction of the arrow A, and as a result the mechanical advantagewould thereby be decreased. It may be understood that a large mechanicaladvantage is achieved when a relatively large vertical motion of thecontact 103 will result in a relatively small horizontal motion. It is asignificant teaching of this invention that the point P of rotation maynot be displaced more than 45 in either direction from the plane 112 asmeasured from the point of contact between the terminal 103 of thecontact 100 (i.e. when the contacts are engaged in a depressedcondition). As the point P is removed from the plane 112, the mechanicaladvantage derived from this leverage system will be decreased to a pointat a displacement of 45, where the mechanical advantage becomes unity.

Referring now to FIG. 5B, the operation of an electrical connectorhaving a plurality of mating contacts will be considered. Morespecifically, the contact assemblies 104 and may be disposed in an XYmatrix which is disposed symmetrically within the assemblies 12 and 14.Further, it may be understood that there are two levers 24 which arerotated about an axis defined by a line running through the center ofthe pins 32. It is desired that when the levers 24 are rotated in eitherdirection that the cam surfaces 28 and 30 abut the pin 34 so as to applya substantially equal pressure upon each of the contacts 10-3 or 100. Inorder to ideally accomplish this object, the line as defined by the pins34 should intercept the line as determined by the centers of pressure.The ter'm center of pressure as applied to electrical connectors may bedefined as that point upon which a force may be applied with the resultthat substantially equal pressure will be exerted upon each of theelectrical contacts associated with the connector. It may be understoodthat there may be several centers of pressure which in this contextdefine a line. By placing the pins 34 upon a line which intercepts acenter of pressure, the motion imparted to the upper assembly 12 by thelever 24 will impart a motion to each of the contacts 103er to 103ealong arcuate paths 110a to e which are substantially identical witheach other. In a manner as discussed above, the pins 32 should be soplaced that the points of rotation of each of the arcuate paths 110a to110e will be within i45 of the plane 112. Further, in order to insurethat the force exerted by the lever 24 through the pin 32 will bepositively applied to each of the contacts 103, the pins 32 are alsopreferably placed within the plane 112. If the pins 32 were placed abovethe plane 112 by a significant distance, the shearing component of theforce so applied would be applied through various moment arms to thecontacts 103 thereby possibly resulting in an unequal and unevenshearing force being applied to different contacts. Though it ispreferred that the pins 34 be placed within the plane 112, it is notedthat in some cases involving a smaller number 0f contacts under variouscircumstances, that the pins 34 may be displaced to some degree from theplane 112 while still obtaining the desired shearing force.

In order to bring the contact assemblies 104 and 90 into engagement, thelevers 24 are rotated in a clockwise direction (as seen in FIG. 1)thereby engaging the cam surfaces 28 against the pins 34. As the upperassembly 12 is being forced downward by the lever 24, the sliding ring80 engages the upper assembly thereby preventing possible combustion ofthe surrounding atmosphere due to electrical discharges between theclosing contacts. As the upper assembly 12 is driven toward the lowerassembly 14, the ring 80 is pressed downward against the springs 82 andeventually the terminals 103 and the plunger contacts 100 engage witheach other. As the terminals 103 are being pressed downward, they arealso being forced in a horizontal direction to thereby wipe this contactsurface 106 across the contact surfaces 102 of the plunger contacts 100.As a result of this motion between the contact surfaces, anycontaminants that may have collected on these contacts will be removed.Finally after the contacts have been engaged, the latching bar 48associated with the handles 26 will catch Within the recess 50 of thedetent `42 thereby holding the levers 24 in the position shown in FIG. 1and thereby locking the assemblies 12 and 14 together.

When it is desired to disengage the contacts the detent mechanism isreleased by pressing downward on the latching bar 48 and inward upon thedetent 42 thereby cornpressing the spring 46 and releasing the latchingbar 48. Then the handles 26 of the levers 24 are rotated in acounterclockwise direction (as seen in FIG. 1) with the cam surface 30engaging the pins 34. As a force is exerted by the cam surface 30against the pin 34, the upper assembly 12 and each of the contacts 103are moved along the arcuate path 110. As explained above, a largemechanical advantage is achieved in accordance with the teachings ofthis invention to impart a high shearing force upon the contact surfacesto thereby break any possible Welds between the contacts.

Since numerous changes may be made in the above described apparatus anddifferent embodiments of the invention may be made without departingfrom the spirit thereof, it is intended that all matter contained in theforegoing description or shown in the accompanying drawings, shall beinterpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. An electrical connector comprising first and second assemblies havingrespectively a plurality of first and second contacts, said first andsecond contacts abutting each other along a limited contact surface,means for biasing and confining the movement of said first contactsalong a path perpendicular to the contact surface of said secondcontacts, and lever means pivotally mounted on one of said assemblies toimpart to the other of said assemblies a motion having a first componentalong said perpendicular path to disengage said assemblies and a secondcomponent transverse to said path to exert a high shearing force uponsaid contacts.

2. An electrical connector as claimed in claim 1, Wherein said levermeans is pivotally mounted at a point disposed substantially within aplane defined by the contact surface when the rst and second contactsare engaged.

3. An electrical connector as claimed in claim 1, wherein said levermeans engages said other assembly to impart an arcuate motion to each ofthe contacts of said other assembly which is substantially similar.

4. An electrical connector as claimed in claim 3, Wherein saidpluralities of first and second contacts are adapted to engage eachother in a plane, said position of said lever means being so disposedthat the point of rotation of said arcuate path imparted to saidcontacts of said other assembly is within 45 of a said plane as measuredfrom the point of interception of said arcuate path and said plane.

5. An electrical connector as claimed in claim 1, wherein said levermeans is adapted to impart an arcuate motion to said other assemblyabout a point located in a plane Which is perpendicular to the planedefined by said contact surface, said point located in saidperpendicular plane at a location within the planar area defined bylines extending in said perpendicular plane from the point ofinterception of said arcuate path and said contact surface at angles i45from said contact surface.

6. An electrical connector as claimed in claim 5, wherein said levermeans includes first and second cam surfaces adapted to engage a memberaffixed to said other assembly for respectively engaging and disengagingsaid first and second assemblies.

7. An electrical connector as claimed in claim 6, Wherein said levermeans includes first and second members pivotally mounted upon saidfirst assembly, a bar interconnecting said first and second members, anddetent means engaging said bar for locking said first and secondassemblies together.

8. An electrical connector as claimed in claim 6, wherein said member isdisposed substantially within the plane defined by said contact surface.

9. An electrical connector as claimed in claim 1, further including acylindrical enclosure which is biased within said connector assembliesto isolate the contacts of said assemblies from hazardous atmospheresexternal to said connector during contact engagement and disengagement.

10. An electrical connector as claimed in claim 1, wherein said firstand second contacts are disposed in sealing material which minimizes theadverse affects of moisture, vibration, and shock.

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3,274,534 9/ 1966 Shortridge 339-95 XR MARVIN A. CHAMPION, PrimaryExaminer P. A. CLIFFORD, Assistant Examiner U.S. C1. X.R.` 339-

